unbound/pythonmod/doc/examples/example3.rst

   1 Response modification
   2 =====================
   3
   4 This example shows how to modify the response produced by the ``iterator`` module.
   5
   6 As soon as the iterator module returns the response, we :
   7
   8 1. invalidate the data in cache
   9 2. modify the response *TTL*
  10 3. rewrite the data in cache
  11 4. return modified packet
  12
  13 Note that the steps 1 and 3 are neccessary only in case, the python module is the first module in the processing chain.
  14 In other cases, the validator module guarantees updating data which are produced by iterator module.
  15
  16 Complete source code
  17 --------------------
  18
  19 .. literalinclude:: ../../examples/resmod.py
  20    :language: python
  21
  22 Testing
  23 -------
  24
  25 Run Unbound server:
  26
  27 ``root@localhost>unbound -dv -c ./test-resmod.conf``
  28
  29 Issue a query for name ending with "nic.cz."
  30
  31 ``>>>dig A @127.0.0.1 www.nic.cz``
  32
  33 ::
  34
  35         ;; global options:  printcmd
  36         ;; Got answer:
  37         ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48831
  38         ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 5
  39
  40         ;; QUESTION SECTION:
  41         ;www.nic.cz.                    IN      A
  42
  43         ;; ANSWER SECTION:
  44         www.nic.cz.             10      IN      A       217.31.205.50
  45
  46         ;; AUTHORITY SECTION:
  47         nic.cz.                 10      IN      NS      e.ns.nic.cz.
  48         nic.cz.                 10      IN      NS      a.ns.nic.cz.
  49         nic.cz.                 10      IN      NS      c.ns.nic.cz.
  50
  51         ;; ADDITIONAL SECTION:
  52         a.ns.nic.cz.            10      IN      A       217.31.205.180
  53         a.ns.nic.cz.            10      IN      AAAA    2001:1488:dada:176::180
  54         c.ns.nic.cz.            10      IN      A       195.66.241.202
  55         c.ns.nic.cz.            10      IN      AAAA    2a01:40:1000::2
  56         e.ns.nic.cz.            10      IN      A       194.146.105.38
  57
  58         ;; Query time: 166 msec
  59         ;; SERVER: 127.0.0.1#53(127.0.0.1)
  60         ;; WHEN: Mon Jan 02 13:39:43 2009
  61         ;; MSG SIZE  rcvd: 199
  62
  63 As you can see, TTL of all the records is set to 10.